Henry Frye wrote:
> TR4's, mine looks to have less camber than others. Michael Porter I
> think may have put his finger on the crux of the issue, my big front
> sway bar is keeping the car from rolling in corners, so I don't need as
> much negative camber dialed in. I wish this was an easy adjustment on a
> TR4. Would make life so much easier...
As I mentioned to Bill Babcock, off-list, the load center on the
tire is through a line from the center of the top ball joint through
the knuckle of the trunnion, and is extended through the bottom of
the tire. That load center is fixed. Static negative camber causes
the tire centerline to move outboard from that load center, so as
negative camber increases, the load center moves to the inboard side
of the tire. (This is why the original factory camber is positive,
since most road driving is straight ahead, and positive camber is
necessary to put the load center at the center of the tire
patch--the factory wanted tires to last through the warranty period.)
With bias-ply tires, the sidewall is much stiffer with increased
inflation, so, not only does the tire not deflect on turns toward
the load center as much as a radial would, but the tire remains
taller and is more affected by negative camber. Running a slightly
over-inflated bias-ply with a camber originally set up for radial
tires could show some of the wear your photos indicated, and a
really stiff front bar could accentuate this wear by not allowing
the car to roll sufficiently to bring the tire to upright.
If you have to run on bias-ply tires due to rules, consider, as a
cheaper fix, going down to a 1" or 7/8" bar in front and adjust tire
pressure to make the car feel right with bias-ply tires before
extensive modifications to the a-arms.
> I have been running cold tire pressures at 24 front and 23 rear. I have
> experimented with lower, and didn't think it felt right. Looks like I
> will be doing more experimenting this week. The Frye Racing Program has
> not started the tire temp thing, so I have no idea what the tire temps
> are. Looks like another gadget for the trailer is needed.
>
> I have the tow set to about 1/8th in. My plan is to buy another set of
> tires and set the toe to Zero before they see the track.
Try zero, but 1/16" toe-out might be necessary.
Cheers.
--
Michael D. Porter
Roswell, NM
Never let anyone drive you crazy when you know it's within walking
distance.
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